mod_http_oauth2: Enforce response type encoded in client_id The client promises to only use this response type, so we should hold them to that. This makes it fail earlier if the response type is disabled or the client is trying to use one that it promised not to use. Better than failing after login and consent.

This module produces more detailed HTTP logs for Prosodys built-in HTTP
server. The format is similar to that of Apache and go into Prosodys
normal logs at the `info` level.